Field of the Invention
The present invention relates to a display device and a method of manufacturing the same, and more particularly to an organic light emitting display device and a method of manufacturing the same.
Discussion of the Related Art
An Organic Light Emitting Display (OLED) device is a self-illuminating device, and is receiving attention as a next-generation flat panel display device thanks to its low power consumption, fast response speed, high luminous efficacy, high brightness, and wide viewing angle.
OLED devices are divided into top emission type OLED devices and bottom emission type OLED devices according to the direction in which light emitted via organic light emitting elements penetrates. Recently, top emission type OLED devices have mainly been used because bottom emission type OLED devices cause deterioration in an aperture ratio.
FIG. 1 is a sectional view illustrating a related art top emission type organic light emitting display device.
The related art top emission type organic light emitting display device includes a substrate 10, a thin film transistor T, a passivation layer 20, a planarization layer 30, a first electrode 40, an auxiliary electrode 50, a bank 60, an organic emission layer 70, and a second electrode 80.
Although not illustrated in FIG. 1, gate lines and data lines are cross-formed on the substrate 10 to define a plurality of pixel areas, and the thin film transistor T is provided in each of the pixel areas.
The passivation layer 20 is provided over the entire surface of the substrate 10 so as to cover the thin film transistor T, and the planarization layer 30 covers the entire surface of the passivation layer 20.
The first electrode 40 is provided on the planarization layer 30 and is electrically connected to the thin film transistor T. In this case, the first electrode 40 may contain a high reflectance material, for example, an Ag alloy layer.
The auxiliary electrode 50 is provided in the same layer as the first electrode 40. The auxiliary electrode 50 is connected to the second electrode 80 and serves to reduce the resistance of the second electrode 80.
The bank 60 is provided at the boundary of each pixel area. The bank 60 is provided between the first electrode 40 and the auxiliary electrode 50 so as to insulate the first electrode 40 and the auxiliary electrode 50 from each other. The organic emission layer 70 is provided on the first electrode 40.
The second electrode 80 is provided over the entire surface of the substrate 10 and is connected to the auxiliary electrode 50. The second electrode 80 may be formed of a thin metallic material having a thickness of hundreds of angstroms (Å) or less.
In the related art top emission type organic light emitting display device described above, the resistance of the second electrode 80 may be somewhat increased because the second electrode 80 is thin. Although the second electrode may be connected to the auxiliary electrode 50 as described above in order to reduce the resistance of the second electrode 80, there is a spatial limitation on any increase in the size of the auxiliary electrode 50 because the auxiliary electrode 50 needs to be provided in the same layer as the first electrode 40. Therefore, there is a limit to the extent to which the resistance of the second electrode 80 may be reduced.
In addition, although not illustrated in FIG. 1, when a source electrode 14 and a drain electrode 15 of the thin film transistor T are provided in the pixel area on the substrate 10, a pad electrode may be provided in a pad area on the substrate 10. However, the pad electrode is vulnerable to corrosion, and corrosion and metal migration may occur in the pad area during subsequent processing. Although a separate process for only the pad area may be added in order to prevent the corrosion and metal migration of the pad area, in this case, the efficiency of production of the display device may be deteriorated due to the addition of the process.